I don't use it right now, but for the fire or earthquake issue, what about CrashPlan? I think they still have an unlimited online backup plan available.
The key is to understand and accept the key reasons for the backup.
local backups are the fastest, and are ideal when worried about product disk failures, but have issues, like the mentioned fire or earthquake or some other issue that affects the location of the primary production and local backup.
Also, if doing phased backups on a spread out schedule, you can protect against malware to a small extent as well. if you have your primary device taken down via a virus and the backup hasn't been infected yet, then you could reformat the entire production disk and still get back up and running relatively quickly. If the virus spreads because whether in use or not, an active disk can get damaged, then this option has screwed you unless your timed backups are mounted only when the backups occur, thus mitigating risk to some extent.
geo-spatially dispersed backups are ideal under most circumstances, but if you go through a lot of data every month, you always run the risk of hitting your internet cap. Many people nowadays have options for internet access that don't entail a cap, but depending on where you live, a capped internet plan may be the only one available, so off-site backups can be problematic for heavy users.
Another option which is ridiculously painful to be diligent about over years and years is having a friend who lives somewhere else with whom you Fedex disks back and forth on a regular basis. This is what I want to do now with a friend of mine who lives in another country, but it's a real pain to be diligent about this, and there's always a risk that disks get damaged during shipping.
At the end of the day, data integrity concerns are just like security concerns. You can keep spending more and more money, but you will never really achieve a perfect plan or series of plans that can cover all situations. Finding the best solution with the disposable income you can continuously put into it over years is about the best you can do.
Good luck.